Leak-resistant bandage systems and methods with hydrophilic foam wound insert for fluid-instillation and/or negative-pressure wound therapies

ABSTRACT

Wound treatment systems and methods (e.g., having hydrophilic wound inserts), such as for negative-pressure and/or fluid-installation wound therapies. Some embodiments include a check-valve assembly between a wound dressing and a vacuum source.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/009,116, filed Jan. 19, 2011 which claims priority to U.S.Provisional Patent Application No. 61/296,822, filed Jan. 20, 2010, thecontents of each of which is incorporated herein in their entirety.

BACKGROUND 1. Field of the Invention

The present invention relates generally to healing of wounds andwound-treatment therapies. More particularly, but not by way oflimitation, the present invention relates to fluid-instillation andnegative-pressure wound therapies.

2. Background Information

Clinical studies and practice have shown that providing a reducedpressure in proximity to a tissue site augments and accelerates thegrowth of new tissue at the tissue site. The applications of thisphenomenon are numerous, but application of reduced pressure has beenparticularly successful in treating wounds. This treatment (frequentlyreferred to in the medical community as “negative pressure woundtherapy,” “reduced pressure therapy,” or “vacuum therapy”) provides anumber of benefits, including faster healing and increased formulationof granulation tissue. Typically, reduced pressure is applied to tissuethrough a wound insert (e.g., a porous pad or other manifold device).The wound insert typically contains cells or pores that are capable ofdistributing reduced pressure to the tissue and channeling fluids thatare drawn from the tissue. The wound insert can be incorporated into awound dressing having other components that facilitate treatment, suchas, for example, a drape (e.g., adhesive surgical drape). Instillationof fluids (e.g., irrigation fluids and/or medicaments) may be used inconjunction with negative pressure wound therapy to promote healingand/or improve efficacy.

While NPWT has been highly successful in the promotion of wound closure,healing many wounds previously thought largely untreatable, somedifficulty remains. With current negative-pressure and/orfluid-instillation systems, leaks may occur at the dressing site due tothe presence of fluid (e.g., instillation fluids, body fluids, etc.)and/or due to such fluids being forced to the perimeter of a woundinsert (e.g., a foam wound insert). Such fluids may interact with theadhesive between the drape and adjacent healthy skin, and can lead tofailure and leakage, thus requiring removal of a wound dressing andapplication of a new dressing. Such removal and re-application can bedetrimental to a patient as the wound is exposed to external atmosphere(e.g., bacteria, contaminants, and the like). Further, fluid forced tothe edges of wound can pool and/or macerate/damage the periwound skinand/or intact skin.

SUMMARY

The present disclosure includes embodiments of methods of forming awound insert, wound-treatment methods, wound dressings, andwound-treatment systems.

Some embodiments of the present check-valve assemblies comprise: ahousing defining a first connection, a second connection, a firstpassageway between the first and second connections, and a secondpassageway between the first and second connections that is distinctfrom the first passageway; a check valve disposed in the firstpassageway and configured to: permit fluid to pass through the checkvalve assembly from the first connection to the second connection if thepressure at the second connection is less than the pressure at the firstconnection; and substantially prevent fluid from passing through thecheck valve from the second connection to the first connection if thepressure at the second connection is greater than the pressure at thefirst connection. In some embodiments, the check valve comprises aduckbill valve. In some embodiments, the check valve comprises a ballvalve. In some embodiments, the first connection comprises a multi-lumenconnection having a first lumen in communication with the firstpassageway, and a second lumen in communication with the secondpassageway, and where the second connection comprises a multi-lumenconnection having a first lumen in communication with the firstpassageway, and a second lumen in communication with the secondpassageway. In some embodiments, the second lumen of the firstconnection is an annular lumen disposed around the first lumen of thefirst connection, and where the second lumen of the second connection isan annular lumen disposed around the first lumen of the secondconnection.

Some embodiments of the present wound-treatment systems comprise: afluid source configured to be coupled to a wound dressing such that thefluid source is actuatable to deliver a fluid to the wound dressing; acheck-valve assembly configured to be coupled to a wound dressing; avacuum source configured to be coupled to the check-valve assembly suchthat the vacuum source is actuatable to apply negative pressure to awound dressing through the check-valve assembly; where the system isconfigured such that (e.g., if a wound dressing is coupled to the fluidsource, the vacuum source, and the check-valve assembly, and the wounddressing is coupled to skin adjacent a wound of a patient such that thewound dressing covers the wound to form a substantially enclosed spaceadjacent the wound) the check-valve assembly: substantially preventsfluid flow through the check-valve assembly toward the wound dressing.In some embodiments, the system can be configured such that thecheck-valve assembly substantially prevents pressure in the spaceadjacent the wound from exceeding atmospheric pressure. Some embodimentsfurther comprise: a wound dressing that comprises: a wound insert; and adrape configured to be coupled to skin adjacent a wound of a patientsuch that the drape covers the wound insert and the wound to form aspace between the drape and the wound; In some embodiments, the woundinsert comprises an open-celled hydrophilic foam. In some embodiments,the wound insert comprises a hydrophobic foam coated with a hydrophiliccoating.

In some embodiments, the check-valve assembly comprises: a housingdefining a first connection configured to be coupled to the wounddressing, a second connection configured to be coupled to the vacuumsource, a first passageway between the first and second connections, anda second passageway between the first and second connections; a checkvalve disposed in the first passageway and configured to: permit fluidto pass through the check valve from the first connection to the secondconnection when the pressure at the second connection is less than thepressure at the first connection; and substantially prevent fluid frompassing through the check valve from the second connection to the firstconnection when the pressure at the second connection is greater thanthe pressure at the first connection.

Some embodiments of the present wound-treatment methods comprise:applying negative pressure through a check-valve assembly and wounddressing to a wound of a patient, the wound dressing coupled to skinadjacent the wound such that the wound dressing covers the wound to forma substantially enclosed space adjacent the wound; and delivering afluid to the wound dressing; where the check-valve assembly isconfigured to: substantially prevent backflow of fluids through thecheck-valve assembly, and substantially prevent pressure in the spacebetween the drape and the wound from exceeding atmospheric pressure. Insome embodiments, the wound dressing comprises: a wound insert; and adrape coupled to skin adjacent the wound such that the drape covers thewound insert and the wound to form the substantially enclosed spacebetween the drape and the wound.

In some embodiments, delivering a fluid comprises activating a fluidsource that is coupled to the wound dressing. In some embodiments,applying negative pressure comprises activating a vacuum source that iscoupled to the wound dressing. In some embodiments, the wound insertcomprises hydrophilic foam. In some embodiments, the wound insertcomprises a hydrophobic foam coated with a hydrophilic coating. In someembodiments, the check-valve assembly comprises: a housing defining afirst connection configured to be coupled to the wound dressing, asecond connection configured to be coupled to the vacuum source, a firstpassageway between the first and second connections, and a secondpassageway between the first and second connections; a check valvedisposed in the first passageway and configured to: permit fluid to passthrough the check valve from the first connection to the secondconnection when the pressure at the second connection is less than thepressure at the first connection; and substantially prevent fluid frompassing through the check valve from the second connection to the firstconnection when the pressure at the second connection is greater thanthe pressure at the first connection.

Some embodiments of the present wound-treatment methods comprise:coupling a wound dressing to skin adjacent a wound of a patient suchthat the wound dressing covers the wound to form a substantiallyenclosed space adjacent the wound; coupling the wound dressing to afluid source such that the fluid source is actuatable to deliver fluidto the wound dressing; coupling the wound dressing to a check-valveassembly and a vacuum source such that the check-valve assembly:substantially prevents backflow of fluids through the check-valveassembly. Some embodiments comprise configuring the system such that thecheck-valve assembly also substantially prevents pressure in the spaceadjacent the wound from exceeding atmospheric pressure. In someembodiments, the wound dressing comprises: a wound insert comprising anopen-celled foam configured to exhibit hydrophilic properties; and adrape; and where coupling the wound dressing comprises: positioning thewound insert on the wound; and coupling the drape to skin adjacent thewound such that the drape covers the wound insert and the wound, andforms a space between the drape and the wound. Some embodiments furthercomprise: applying a negative pressure to the wound through thecheck-valve assembly and the wound dressing; and delivering a fluid tothe wound through the wound dressing. In some embodiments, the woundinsert comprises hydrophilic foam. In some embodiments, the wound insertcomprises a hydrophobic foam coated with a hydrophilic coating.

Any embodiment of any of the present systems and/or methods can consistof or consist essentially of—rather thancomprise/include/contain/have—any of the described steps, elements,and/or features. Thus, in any of the claims, the term “consisting of” or“consisting essentially of” can be substituted for any of the open-endedlinking verbs recited above, in order to change the scope of a givenclaim from what it would otherwise be using the open-ended linking verb.

Details associated with the embodiments described above and others arepresented below.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings illustrate by way of example and not limitation.For the sake of brevity and clarity, every feature of a given structureis not always labeled in every figure in which that structure appears.Identical reference numbers do not necessarily indicate an identicalstructure. Rather, the same reference number may be used to indicate asimilar feature or a feature with similar functionality, as maynon-identical reference numbers.

FIG. 1 depicts a side view of one embodiment of the present wounddressings having one of the present wound inserts and coupled to a woundsite and to a wound treatment apparatus.

FIG. 2A depicts an enlarged side view of the wound insert of FIG. 1.

FIGS. 2B and 2C depict photographs showing experimental comparisons offluid interaction of hydrophilic wound inserts relative to that of aprior hydrophobic wound insert.

FIG. 3 depicts a schematic block diagram of one embodiment of a woundtreatment apparatus that can comprise and/or be coupled to and/or beused with the present wound dressings and/or wound inserts.

FIG. 4 depicts a perspective view of one of the present check-valveassemblies.

FIG. 5 depicts a cross-sectional side view of the check-valve assemblyof FIG. 4.

FIG. 6 depicts a cross-sectional side view of the check-valve assemblyof FIG. 4.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The term “coupled” is defined as connected, although not necessarilydirectly, and not necessarily mechanically; two items that are “coupled”may be integral with each other. The terms “a” and “an” are defined asone or more unless this disclosure explicitly requires otherwise. Theterms “substantially,” “approximately,” and “about” are defined aslargely but not necessarily wholly what is specified, as understood by aperson of ordinary skill in the art.

The terms “comprise” (and any form of comprise, such as “comprises” and“comprising”), “have” (and any form of have, such as “has” and“having”), “include” (and any form of include, such as “includes” and“including”) and “contain” (and any form of contain, such as “contains”and “containing”) are open-ended linking verbs. As a result, a methodthat “comprises,” “has,” “includes” or “contains” one or more stepspossesses those one or more steps, but is not limited to possessing onlythose one or more steps. Likewise, a wound dressing that “comprises,”“has,” “includes” or “contains” one or more elements possesses those oneor more elements, but is not limited to possessing only those elements.For example, in a wound dressing that comprises a wound insert and adrape, the wound dressing includes the specified elements but is notlimited to having only those elements. For example, such a wounddressing could also include a connection pad.

Further, a device or structure that is configured in a certain way isconfigured in at least that way, but it can also be configured in otherways than those specifically described.

Referring now to the drawings, and more particularly to FIG. 1, showntherein is an embodiment of one of the present wound treatment system10. In the embodiment shown, apparatus 10 comprises a wound-treatmentapparatus 14, and a wound dressing 18 coupled to apparatus 14 by aconduit 22. As shown, dressing 18 is configured to be coupled to (and isshown coupled to) a wound 26 of a patient 30. More particularly, in theembodiment shown, dressing 18 comprises a wound insert 34 and a drape38. As shown, wound insert 34 is configured to be positioned (and isshown positioned) on wound 26 (e.g., on or adjacent to wound surface42), and/or drape 38 is configured to be coupled to (and is showncoupled to) skin 46 of the patient adjacent to wound 26 such that drape38 covers wound insert 34 and wound 26, and forms a space 50 betweendrape 38 and wound 26 (e.g., wound surface 42).

Apparatus 14 can comprise, for example, a vacuum source configured to beactuatable (and/or actuated) to apply negative pressure (e.g., viaconduit 22) to wound dressing 18, a fluid source configured to beactuatable (and/or actuated) to deliver (e.g., via conduit 22) a fluid(e.g., an installation fluid such as a medicinal fluid, antibacterialfluid, irrigation fluid, and or the like) to wound dressing 18. System10 can be implemented and/or actuated and/or coupled to patient 30 inany of various configurations and/or methods similar to those describedin the prior art. For example, various wound therapy systems andcomponents are commercially available through and/or from KCI USA, Inc.of San Antonio, Tex., U.S.A.

Conduit 22 can comprise a single lumen conduit (e.g., switched between avacuum source and/or a fluid source and apparatus 14), or can comprisemultiple single-lumen conduits or a multi-lumen conduit such that, forexample, fluid can be delivered and/or negative pressure can be appliedto wound dressing 18 individually and/or simultaneously. Additionally,conduit 22 can comprise, for example, a first lumen for the applicationof negative pressure and/or fluid delivery, and at least one additionallumen for coupling to pressure sensor(s) to sense pressure (absolutepressure) or negative pressure (relative to atmospheric pressure)between drape 38 and surface 42. In some embodiments, conduit 22 cancomprise multiple lumens (e.g., as in a single conduit with a centrallumen for application of negative pressure and/or fluid delivery, andone or more peripheral lumens disposed adjacent or around the centrallumen such that the peripheral lumens can be coupled to a pressuresensor to sense a pressure or negative pressure between drape 38 andsurface 42 (e.g. in space 50). The lumens may be arranged with a centrallumen and other lumens disposed radially around the central lumen, or inother suitable arrangements. The lumens may also be provided in separateconduits. In the embodiment shown, system 10 further comprises a wounddressing connection pad 54 configured to be coupled (and is showncoupled) to conduit 22. One example of a suitable connection pad 54 isthe “V.A.C. T.R.A.C.® Pad,” commercially available from KCI. One exampleof a suitable drape 38 includes the “V.A.C.® Drape” commerciallyavailable from KCI. Another example of a connection pad 54 is disclosedin U.S. patent application Ser. No. 11/702,822, published as Pub. No. US2007/0219512 A1.

One example of a suitable drape 38 includes the “V.A.C.® Drape”commercially available from KCI USA, Inc. (and its affiliates) of SanAntonio, Tex., U.S.A.

Referring now to FIG. 2A, a side view of wound insert 34 is shown. Woundinsert 34 has an upper side 100, a lower side 104, lateral sides 108,112, and interior volume 116. Although only one side is shown of woundinsert 34, it will be understood by those of ordinary skill in the artthat wound insert 34 includes a three-dimensional rectangular volumehaving a depth extending perpendicular to the side shown. In otherembodiments, wound insert 34 can have any suitable shape, such as, forexample, a round cylindrical shape, a fanciful shape, or may be trimmedto fit an irregular shape of a wound (e.g., 26 and/or wound surface 42).

The present embodiments of wound insert 34 comprise a foam (e.g., anopen-celled foam, which may also be reticulated) that is configured toexhibit hydrophilic properties. In contrast to hydrophobic foamstraditionally used with NPWT systems and methods, the hydrophilicproperties of wound insert 34 provide improved movement of fluid (e.g.,liquids such as instillation fluids, body fluids, exudate, and the like)through the wound insert, such that fluid is encouraged to travelthrough wound insert 34 rather than around the wound insert 34 oradjacent to the interface between drape 38 and skin 46.

With traditional hydrophobic wound inserts, fluid typically travels in apath such that the fluid minimizes contact with the foam, and such thatfluid is repelled from the foam and may generate pressure between thefoam and interface between drape 38 and skin 46. As such, hydrophobicwound inserts may force drape 38 away from skin 46 about the perimeterof wound 26. More particularly, with traditional hydrophobic woundinserts, very little of the fluid is retained or transferred through thefoam itself. Because fluid may be forced outward from the hydrophobicwound insert, the fluid can generate a positive pressure (in excess ofatmospheric pressure) at the interface between the drape and skinadjacent to the wound. This can lead to a ballooning effect which canstress the interface between the drape and the adjacent skin, and canlead to failure of the adhesive generally used to couple the drape tothe skin. The ballooning effect can be particularly problematic ifnegative pressure is applied cyclically (e.g., on and off) and if fluidsare introduced into the wound (e.g., instillation therapy).

However, with the present hydrophilic wound inserts 34, fluid can travelthrough or in at least a portion of wound insert 34 (e.g., evenlydispersed throughout wound insert 34), thus decreasing the positivepressure within the space 50 and at the interface between drape 38 andskin 46. As such, with the present hydrophilic wound inserts 34, fluidtypically will not reach the interface between drape 38 and skin 46 asquickly, such that the integrity of adhesive or the like coupling drape38 to skin 46 is maintained longer and permits more durable adhesionbetween drape 38 and skin 46. In this way, wound dressings 18 comprisingdrape 38 and wound insert 34 are typically more durable and/or lessprone to failure.

As illustrated in FIG. 1, embodiments of the present wound dressings 18comprise a wound insert 34 configured to be positioned on a wound 26(e.g., wound surface 42) of a patient (e.g., 30), the wound insertcomprising a foam (e.g., an open-celled foam, which may also bereticulated) configured to exhibit hydrophilic properties; and a drape38 configured to be coupled to skin 46 of the patient adjacent the woundsuch that drape 38 covers wound insert 34 and wound 26 and forms a space50 between the drape and the wound. Wound insert 34 can comprise anysuitable material and/or combination of materials that permit woundinsert 34 to exhibit hydrophilic properties. For example, in someembodiments, wound insert 34 comprises an open-celled hydrophobic foamthat is coated with a hydrophilic coating (e.g., a coating configured tocause the hydrophobic foam to exhibit hydrophilic properties). In someembodiments, the hydrophilic coating comprises polyvinyl alcohol (PVOH),plasticizer (e.g., triethyl citrate, or the like), hydrophilicpolyurethane, gelatin, hyaluronic acid, heparin, and/or any othersuitable coating configured to cause the coated hydrophobic foam toexhibit hydrophilic properties.

Embodiments of the present methods of forming wound insert 34 comprise:applying a hydrophilic coating to an open-celled (which may also bereticulated) hydrophobic foam, where the coating is configured to causethe foam to exhibit hydrophilic properties. In some embodiments, thehydrophilic coating comprises polyvinyl alcohol (PVOH), plasticizer(e.g., triethyl citrate, or the like), hydrophilic polyurethane,gelatin, hyaluronic acid, heparin, and/or any other suitable coatingconfigured to cause the coated hydrophobic foam to exhibit hydrophilicproperties. In such embodiments, the coating can comprise a fluidcoating, such as those that may be applied to a foam in a liquid stateand dried, cross-linked, and/or otherwise cured to coat the foam (e.g.,such that the coating is stable on the foam even in the presence of afluid or liquid).

Referring now to FIGS. 2B and 2C, embodiments of the present woundinserts 34 a and 34 b are shown adjacent to a prior hydrophobic woundinsert 36. In FIG. 2B, wound inserts 34 a, 34 b, and 36 are shown with alower end disposed in a fluid. Wound insert 34 a comprises a hydrophobicfoam coated with a hydrophilic coating. Wound insert 34 b comprises ahydrophilic foam. In FIG. 2C, wound inserts 34 a, 34 b, and 36 are shownremoved from the fluid such that the dispersion of fluid in each of thewound inserts can be seen relative to one another. As shown, hydrophilicfoam wound inserts 34 a and 34 b permit fluid to traverse upward anddisperse throughout wound inserts 34 a and 34 b. In contrast,hydrophobic wound insert 36 expands and substantially repels the fluidfrom traversing, entering, or otherwise becoming dispersed throughoutwound insert 36. In this way, wound insert 36 effectively forces fluidto the edges of wound insert 36 such that if wound insert 36 is used ina wound dressing 18, the fluid that is repelled from wound insert 36 canexert an outward force on the interface between drape 38 and skin 46,and/or can infiltrate the adhesive between drape 38 and skin 46, asdescribed above. In contrast, and as illustrated in FIGS. 2B and 2C,hydrophilic foam wound inserts 34 a and 34 b permit fluid to traversewound inserts 34 a and 34 b to substantially prevent and/or reduceoutward forces on drape 38 (e.g., caused by positive pressure betweendrape 38 and wound 30), and/or fluid infiltration of adhesive betweendrape 38 and skin 46.

Embodiments of the present wound treatment methods may be betterunderstood with reference to FIG. 3. FIG. 3 depicts the schematic blockdiagram of one embodiment of system 10. In the embodiment shown, wounddressing 18 is coupled to apparatus 14, and apparatus 14 comprises avacuum source 200 (e.g., a vacuum pump and/or the like) coupled to acanister 204 (e.g., configured to receive exudate and or the like fromwound dressing 18) by way of a conduit 208. In the embodiment shown,apparatus 14 further comprises: a pressure sensor 212 having a firstpressure transducer 216 coupled to conduit 208 by way of conduit 220and/or tee-fitting 224, and a second pressure transducer 228 coupled tocanister 204 and/or wound dressing 18 by way of conduit 232. Pressuresensor 212 is configured to sense the negative pressure in wounddressing 18 and/or any of the various conduits coupled to wound dressing18, pressure sensor 212, and/or vacuum source 200.

In the embodiment shown, apparatus 14 further comprises a pressurerelease valve 236 coupled to conduit 232. Further, in the embodimentshown, canister 204 and vacuum source 200 are coupled to wound dressing18 by way of a conduit 238, a check-valve assembly 240 (which may alsobe referred to as a one-way valve assembly 240), and a conduit 242. Moreparticularly, conduit 238 couples canister 204 to check-valve assembly240, and conduit 242 couples check-valve assembly 240 to wound dressing18. In the embodiment shown, canister 204 comprises a filter 244 at ornear an outlet of canister 204 to prevent liquid or solid particles fromentering conduit 208. Filter 244 can comprise, for example, a bacterialfilter that is hydrophobic and/or lipophilic such that aqueous and/oroily liquids will bead on the surface of the filter. Apparatus 14 can beconfigured such that during operation of vacuum source 200 will providesufficient airflow through a filter 244 that the pressure drop acrossfilter 244 is not substantial (e.g., such that the pressure drop willnot substantially interfere with the application of negative pressure towound dressing 18 from vacuum source 200).

In various embodiments, such as the one shown in FIG. 3, apparatus 14can be configured such that as soon as liquid in the canister reaches alevel where filter 244 is occluded, a much-increased negative (orsubatmospheric) pressure occurs in conduit 208 and is sensed bytransducer 216. Transducer 216 can be connected to circuitry thatinterprets such a pressure change as a filled canister and signals thisby means of a message on an LCD and/or buzzer that canister 204 requiresemptying and/or replacement, and/or that automatically shuts off ordisables vacuum source 200.

Apparatus 14 can also be configured to apply intermittent negative (orsubatmospheric) pressure to the wound site, and/or such that pressurerelief valve 236 enables pressure at the wound site to be brought toatmospheric pressure rapidly. Thus, if apparatus 14 is programmed, forexample, to relieve pressure at ten-minute intervals, at these intervalspressure relief valve 236 can open for a specified period, allow thepressure to equalize at the wound site, and then close to restore thenegative pressure. It will be appreciated that when constant negativepressure is being applied to the wound site, valve 236 remains closed toprevent leakage to or from the atmosphere. In this state, it is possibleto maintain negative pressure at the wound site without running and/oroperating pump 200 continuously, but only from time to time orperiodically, to maintain a desired level of negative pressure (i.e. adesired pressure below atmospheric pressure), which is sensed bytransducer 216. This saves power and enables the appliance to operatefor long periods on its battery power supply.

In the embodiment shown, apparatus 14 further comprises a fluid source248 coupled to wound dressing 18 by way of a conduit 252 such that suchthat fluid source 248 is actuatable to deliver a fluid to wound dressing18 (e.g., to the wound through the wound dressing). Fluid source 248 canbe any suitable mechanism capable of delivering fluid, such as, forexample, a syringe, a fluid pump, and/or the like. Typically, in systemssuch as apparatus 14 that do not have a check-valve assembly, beforefluid is delivered to the wound dressing, the wound dressing (e.g., thespace in the wound dressing) is returned to atmospheric pressure, andthe conduit (e.g., conduit 238) between the wound dressing and thecanister is clamped to prevent backflow of fluids of fluids through thecheck-valve assembly. This can lead to leakage and/or rupture of theadhesive boundary between the wound dressing 18 and the skin of thepatient, because as fluid is delivered to the sealed (or substantiallysealed) environment within the wound dressing, it can pressurize thewound dressing and/or force fluids to the boundary of the wounddressing.

However, in the embodiment shown, check-valve assembly 240 is configuredto substantially prevent (prevent up to all, but may be subject to someleakage, such as during transition between open and closedconfigurations, as described in this disclosure) backflow (flow backtowards wound dressing 18) of fluids through check-valve assembly 240(e.g., from conduit 238 to conduit 242) and/or into wound dressing 18;and to substantially prevent pressure in the space adjacent the wound(e.g., within wound dressing 18) from exceeding atmospheric pressure,such as when pressure release valve 236 is opened to prevent canister204 from exceeding atmospheric pressure (or if canister 204 is otherwisevented to prevent conduit 238 from exceeding atmospheric pressure). Itshould be appreciated that some backflow may occur from conduit 242 intowound dressing, but will be substantially prevented upstream ofcheck-valve assembly 240 (e.g., from conduit 238). In some embodiments,backflow from conduit 242 is minimized by placing or disposingcheck-valve assembly 240 adjacent to wound dressing 18 (e.g., within 1,2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 cmof wound dressing 18) and/or making check-valve assembly 240 a part ofwound dressing 18 (e.g., such that check valve assembly 240 isdisposable with wound dressing 18). For example, in some embodiments,check-valve assembly 240 is disposed within 5 cm or less of wounddressing 18 such that the volume is minimized within conduit 242 betweencheck-valve assembly 240 and wound dressing 18.

In the embodiment shown, negative pressure (a pressure below atmosphericpressure) in the wound dressing 18 can be maintained (e.g., the wounddressing 18 need not be returned to atmospheric pressure) prior todelivering fluid to the wound dressing, such that backflow issubstantially prevented through the check-valve assembly 240 into wounddressing 18, and such that as pressure in wound-dressing 18 increases tothe pressure in conduit 238, check-valve assembly will permit the flowof fluids (and the release of pressure) from one side of the check-valveassembly to the other (e.g., from wound dressing 18 and conduit 242,through check-valve assembly 240, to conduit 238). In this way,check-valve assembly 240 is configured to maintain negative pressure atwound dressing 18 prior to instillation therapy (delivery of fluid tothe wound dressing), thereby minimizing liquid leaks caused fromballooning and/or failure of the drape adhesive, and to minimize theamount of fluid that is wasted. For example, during normal operation,negative pressure can be maintained for a period of time at the wounddressing, and atmospheric pressure can be introduced at the canister(e.g., by venting canister 204 to atmosphere to cause the pressure incanister 204 to increase to atmospheric pressure (with the correspondingdecrease in “negative pressure”)). As fluid is metered into the wounddressing, the pressure at the wound site will increase until it reachesatmospheric pressure. Once the pressure in wound dressing 18 (andconduit 242) reaches or exceeds the pressure in conduit 238 (andcanister 204), check-valve assembly 240 will permit flow across thecheck-valve assembly from conduit 242 to conduit 238, and therebyprevent the wound dressing from overfilling.

Referring now to FIGS. 4-6, an embodiment 240 a is shown of the presentcheck-valve assemblies. More particularly, FIG. 4 depicts a perspectiveview of check-valve assembly 240 a; FIG. 5 depicts a cross-sectionalside view of check-valve assembly 240 a; and FIG. 6 depicts across-sectional side view of check-valve assembly 240 a. In theembodiment shown, check-valve assembly 240 a comprises: a housing 300defining a first connection 304, and a second connection 308. Housing300 further defines a first passageway 312 between first and secondconnections 304 and 308, and a second passageway 316 between first andsecond connections 304 and 308. As shown, second passageway 316 isdistinct from (e.g., separate from and not in fluid communication with)first passageway 312. In the embodiment shown, check-valve assembly 240a further comprises a check valve 320 disposed in first passageway 312,and configured to: permit fluid to pass through check valve 320 (e.g.,through first passageway 312) from first connection 304 to secondconnection 308 if the pressure at second connection 308 is less than thepressure at first connection 304. In the embodiment shown, check valve320 is further configured to substantially prevent (prevent up to all,but may be subject to some leakage, such as during transition betweenopen and closed configurations, as described in this disclosure) fluidfrom passing through check valve 320 from first connection 304 to secondconnection 308 if the pressure at second connection 308 is greater thanthe pressure at first connection 304. For example, in the apparatus ofFIG. 3, first connection 304 of check-valve assembly 240 a would becoupled to conduit 242, and second connection 308 would be coupled toconduit 238.

In the embodiment shown, housing 300 comprises a first member 324 and asecond member 328 configured to be coupled to one another by anysuitable structure or method, such as, for example, with interlockingtabs, adhesive, screws, rivets, ultrasonic welding, thermal welding, orthe like. In the embodiment shown, second member 328 has a coupling end332 (e.g., opposing second connection 308) having a groove 336 (e.g., aperipheral groove, as shown), and first member 324 has a coupling end340 (e.g., opposing first connection 304) having a ridge 344 (e.g., aperipheral ridge, as shown) configured to extend into groove 336 whenthe first and second members 324 and 328 are coupled to one another, asshown in FIGS. 5 and 6, such that ridge 344 and groove 336 cooperate toimprove the connection (e.g., the strength and/or integrity of theconnection) between first and second members 324 and 328. In theembodiment shown, first and second members 324 and 328 are configured tobe coupled to one another with adhesive and/or by ultrasonic welding. Asshown, first and second members 324 and 328 cooperate to define firstand second passageways 312 and 316, and/or check valve 320 cooperateswith first and second members 324 and 328 to seal between first andsecond housings 324 and 328 such that first passageway 312 is distinctfrom second passageway 316 (e.g., fluid communication is substantiallyprevented between first and second passageways 312 and 316).

In the embodiment shown, first connection 304 comprises a multi-lumenconnection having a first lumen 348 in communication with firstpassageway 312, and a second lumen 352 in communication with secondpassageway 316. Additionally, in the embodiment shown, second connection308 comprises a multi-lumen connection having a first lumen 356 incommunication with first passageway 312, and a second lumen 360 incommunication with second passageway 316. More particularly, in theembodiment shown, second lumen 352 of first connection 304 is an annularlumen disposed around first lumen 348 of first connection 304; andsecond lumen 360 of second connection 308 is an annular lumen disposedaround first lumen 356 of second connection 308.

In the embodiment shown, check valve 320 is a duckbill valve. In theembodiment shown, valve 320 comprises an enlarged base portion 364configured to fit around the perimeter of first passageway 312 inhousing 300. Additionally, first and second members 324 and 328 (and/orenlarged base portion 364) are configured such that when valve 320 isdisposed in first passageway 312, and first and second members 324 and328 are coupled to one another, as shown in FIGS. 5 and 6, the first andsecond members compress at least a portion of enlarged base portion 364to provide a seal between first and second members 324 and 328 and tosubstantially prevent fluid communication between first and secondpassageways 312 and 316 within housing 300. More particularly, in theembodiment shown, first member 324 comprises a circular protrusion 368having an angled or chamfered outer edge; and second member 328comprises an angled ledge 372. Protrusion 368 and ledge 372 areconfigured such that when valve 320 is disposed in first passageway 312,and first and second members 324 and 328 are coupled to one another:protrusion 368 extends into the middle of and presses against and innersurface of enlarged base portion 364, and ledge 372 presses against anouter surface of enlarged base portion 364, such that protrusion 368 andledge 372 cooperate to compress enlarged base portion 364 around theperimeter of first passageway 312, as shown in FIGS. 5 and 6.

In the embodiment shown, the multi-lumen configuration of first andsecond connections permits check-valve assembly 240 a to be coupled to amulti-lumen conduit (e.g., a multi-lumen PVC tubing) between a wounddressing (e.g., 18) and an apparatus comprising a vacuum source (e.g.,200) and a pressure sensor (e.g., pressure transducer 212). For example,some commercially available NPWT apparatuses are configured to combinethe vacuum or negative pressure conduit (e.g., 240, 242) and thepressure-sensor conduit (e.g., 232) into a single multi-lumen conduit(not shown), such that the pressure-sensor conduit comprises a pluralityof peripheral lumens disposed around a central vacuum or negativepressure lumen in the multi-lumen conduit. To ensure communicationbetween peripheral pressure-sensor lumens, first member 324 includes ashelf 376 in annular lumen 352, and second member 328 includes a shelf380 in annular lumen 360, to prevent the peripheral pressure lumens in amulti-lumen tube from being blocked by first member 324, such thatcommunication is permitted between the peripheral pressure-sensor lumensand the second passageway 316.

In the embodiment shown, second member 328 comprises indents 384 (twoindents 384 on opposite sides of first passageway 312), and check valve320 comprises protrusions 388 (two protrusions 388 on opposite sides ofvalve 320) that correspond to indents 384, such that indents 384 andprotrusions 388 cooperate to orient valve 320 in body 300 and/or toprevent rotation of valve 320 in body 300. Although valve 320 is shownas a duckbill valve, in other embodiments check valve 320 can comprise aball valve or an umbrella valve.

Some embodiments of the present wound-treatment methods comprise:applying negative pressure through a check-valve assembly (e.g., 240,240 a) and wound dressing (e.g., 18) to a wound (e.g., 26) of a patient(e.g., 30), the wound dressing coupled to skin (e.g., 46) adjacent thewound such that the wound dressing covers the wound to form asubstantially enclosed space (e.g., 50) adjacent the wound. Someembodiments comprise delivering a fluid to the wound dressing (e.g.,from a fluid source 248). In some embodiments, the check-valve assemblyis configured to: substantially prevent backflow of fluids through thecheck-valve assembly, and substantially prevent pressure in the spacebetween the drape and the wound from exceeding atmospheric pressure. Insome embodiments, delivering a fluid comprises activating a fluid source(e.g., 248) that is coupled to the wound dressing. In some embodiments,applying negative pressure comprises activating a vacuum source (e.g.,200) that is coupled to the wound dressing.

Some embodiments of the present wound-treatment methods comprise:coupling a wound dressing (e.g., 18) to skin (e.g., 46) adjacent a wound(e.g., 26) of a patient (e.g., 30) such that the wound dressing coversthe wound to form a substantially enclosed space (e.g., 50) adjacent thewound. Some embodiments comprise: coupling the wound dressing to a fluidsource (e.g., 248) such that the fluid source is actuatable to deliverfluid to the wound dressing. Some embodiments comprise: coupling thewound dressing to a check-valve assembly (e.g., 240, 240 a) and a vacuumsource (e.g., 200) such that the check-valve assembly: substantiallyprevents backflow of fluids through the check-valve assembly. In someembodiments, the system can be configured such that the check-valveassembly substantially prevents pressure in the space adjacent the woundfrom exceeding atmospheric pressure, such as when pressure release valve236 is opened to prevent canister 204 from exceeding atmosphericpressure (or if canister 204 is otherwise vented to prevent conduit 238from exceeding atmospheric pressure). In some embodiments, the wounddressing comprises a wound insert (e.g., 34) and a drape (e.g., 38), andcoupling the wound dressing comprises: positioning the wound insert onthe wound; and coupling the drape to skin adjacent the wound such thatthe drape covers the wound insert and the wound, and forms a spacebetween the drape and the wound. Some embodiments comprise: applying anegative pressure to the wound through the check-valve assembly and thewound dressing; and delivering a fluid to the wound through the wounddressing.

Embodiments of any of the present methods can utilize, include the useof, and/or otherwise comprise any of the apparatuses, wound dressings,wound inserts, and/or check-valve assemblies described in thisdisclosure. In any of the present wound-treatment methods, fluid can bedelivered to the wound dressing 18 prior to applying negative pressureto wound dressing 18, negative pressure can be applied to wound dressing18 prior to fluid being delivered to wound dressing 18, and/or fluid canbe delivered wound dressing 18 simultaneously with negative pressurebeing applied to wound dressing 18.

In some embodiments of the present wound-treatment methods, a skinpreparation can be used in combination with the present wound dressings18 to improve the adhesion and durability of the interface between drape38 and skin 46, such as, for example, to mitigate and/or reduce leaks.For example, skin 46 adjacent wound 26 can be cleaned and coated with acoating that is impervious and/or insoluble in water. In this way,adhesion between drape 28 and coated skin 46 can be improved and/or canbe made more durable by reducing its susceptibility to infiltration fromwater-based installation fluids that may be delivered to wound dressing18 and/or to space 50. By way of another example, a coating can beapplied to the skin (e.g., in a manner similar to certain adhesives)that dries or sets into a layer on top of the skin that is durableenough to reduce and/or prevent maceration of the skin to reduce traumato the underlying skin upon removal of the drape from the skin.

The present embodiments of the systems, methods, and when dressingsreduce the risks associated with fluid instillation by delaying and/orminimizing fluid contact and/or infiltration of the interface betweendrape 38 and skin 46 that could degrade adhesive that is often used tocouple drape 38 to skin 46 when wound dressing 18 is coupled to apatient 30. Additionally, improved fluid management can decrease thepositive pressure that might otherwise be generated at the interfacebetween drape 38 and skin 46 so as to reduce mechanical strains thatwould otherwise act to pull drape 38.

The various illustrative embodiments of devices, systems, and methodsdescribed herein are not intended to be limited to the particular formsdisclosed. Rather, they include all modifications and alternativesfalling within the scope of the claims.

The claims are not intended to include, and should not be interpreted toinclude, means-plus- or step-plus-function limitations, unless such alimitation is explicitly recited in a given claim using the phrase(s)“means for” or “step for,” respectively.

It will be understood that the benefits and advantages described abovemay relate to one embodiment or may relate to several embodiments. Itwill further be understood that reference to ‘an’ item refers to one ormore of those items, unless otherwise specified.

The steps of the methods described herein may be carried out in anysuitable order, or simultaneously where appropriate.

Where appropriate, aspects of any of the examples described above may becombined with aspects of any of the other examples described to formfurther examples having comparable or different properties andaddressing the same or different problems.

It will be understood that the above description of preferredembodiments is given by way of example only and that variousmodifications may be made by those skilled in the art. The abovespecification, examples and data provide a complete description of thestructure and use of exemplary embodiments. Although various embodimentshave been described above with a certain degree of particularity, orwith reference to one or more individual embodiments, those skilled inthe art could make numerous alterations to the disclosed embodimentswithout departing from the scope of this invention.

The invention claimed is:
 1. A wound-treatment system comprising: awound dressing comprising: a wound insert comprising a hydrophobic foamcoated with a hydrophilic material and configured to be disposedadjacent a wound, and; a drape configured to cover the wound insert andthe wound; a fluid source configured to be fluidly coupled to the wounddressing; a vacuum source configured to be fluidly coupled to the wounddressing; and a check valve assembly comprising: a first member having afirst connection configured to be fluidly coupled to the wound dressing,a first lumen, and a second annular lumen disposed around the firstlumen, wherein the first lumen and the second annular lumen extend fromthe first connection through the first member, a second member having asecond connection configured to be fluidly coupled to the vacuum source,a first lumen, and a second annular lumen disposed around the firstlumen, wherein the first lumen and the second annular lumen extend fromthe second connection through the second member, a check valve disposedin a passageway formed between the first lumens of the first and secondmember, and wherein the second annular lumens of the first and secondmember are fluidly coupled so that they are not in fluid communicationwith the first lumens of the first and second member and the passageway.2. The system of claim 1, wherein the hydrophobic foam comprises anopen-cell foam.
 3. The system of claim 2, wherein the open-cell foam isa reticulated open-cell foam.
 4. The system of claim 1, wherein thehydrophilic material comprises polyvinyl alcohol.
 5. The system of claim1, wherein the hydrophilic material comprises a plasticizer.
 6. Thesystem of claim 1, wherein the hydrophilic material compriseshydrophilic polyurethane.
 7. The system of claim 1, wherein thehydrophilic material comprises gelatin.
 8. The system of claim 1,wherein the hydrophilic material comprises hyaluronic acid.
 9. Thesystem of claim 1, wherein the hydrophilic material comprises heparin.